In a mounting device of this type, disclosed in Applicant's FR No. 88.14048, the stationary jaw of the locking system delimits, in its lower part, a guidance slide track for a guide piece connected to the movable jaw constituted by an axial extension of the latter. This known mounting device calls for the embedding of the guide piece of the locking slide in the associated part of the slide track. An arrangement of this kind allows the stresses exerted on the movable jaw during cross-country skiing to be transmitted to the slide track, but requires that the jaw be stationary and that the slide track which it delimits be made of a treated steel capable of bearing the additional stresses generated in the slide track. A steel slide track of this kind also poses manufacturing problems because of the complexity of the shapes to be produced.